Tapping and pouring system for molten metals

ABSTRACT

System ( 2 ) for tapping a high-temperature molten material, especially a molten metal, from a bath ( 8 ) and pouring it into a mould, comprising a mobile container ( 6 ) capable of moving with respect to an element ( 26 ) in such as way as, on the one hand, said container ( 6 ) may be plunged into the bath ( 8 ) to take some liquid and, on the other hand, lift the container ( 6 ) above a particular level for forcing the liquid to fall down with gravity through an aperture ( 10 ) along the wall. The system ( 2 ) does not imply high costs and allows to pour accurate volumes of molten material.

FIELD OF THE INVENTION

The invention relates to a system for tapping and pouring hightemperature molten material, comprising a first container and a secondcontainer capable of being introduced into the first container.

PRIOR ART

Many systems are known in the art to tap a particular amount or volumeof high temperature molten material from a furnace and pour it, forinstance into a mould for use in metal die-casting operations.

One way to perform this operation is to make use of a ladle capable ofbeing plunged into a bath of molten material, and further capable oftaking out a particular amount of said molten material, transporting itfor instance on top of a mould to be filled and pouring the moltenmaterial into the mould, either by tilting the ladle and by letting themolten material going through a spout or by opening a valve and lettingthe molten material to drain away through said valve.

A system using the above principle is the “Hodler system”, asillustrated in FIG. 219 of page 126 of “Technologie de la Fonderie enMoules Metalliques, Fonderie sous pression”, Edition techniques desindustries de la fonderie, Paris 1968. In said system, a container isplunged into a crucible which contains molten metal. Said container isthen filled up with molten metal. The container is then removed from thecrucible by mechanical means and carried to a place above a mould or achannel leading to a mould. A valve located on the bottom of the mobilecontainer is opened to let the liquid drain away towards the mould.

When these systems are used with important amounts of high-temperaturemolten material and while they are required to tap and pour veryaccurate amounts of such material they often cannot be manually drivenand require elaborate mechanisms to plunge the container into thecrucible, move said container to carry the material and open a valve orto tilt said container if needed. These mechanisms are expensive tomake, install and maintain and present safety hazards, such as the riskof molten material dripping.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a system for tapping andpouring an accurate amount or volume of high-temperature moltenmaterial, especially a molten metal, the system being less expensive tomake, install and maintain and being safer.

To this end, the system is characterized in that the second container isarranged inside the first container and, in operation, remains insideand in contact with the first container, the first and second containershare a common inner wall comprising an exit for letting the moltenmaterial flowing out of the system, and the system comprises means formoving the second container in respect to the common inner wall to andfro a filling position for filling the second container with moltenmaterial present in the first container and a pouring position forpouring molten material from the second container through the exit.

The system according to the invention is such that, in operation, thefirst container is filled with molten material. Moreover, the secondcontainer is arranged inside the first container and executes inoperation a movement inside the first container, i.e. the secondcontainer remains inside the first container, thus not causing drippingof molten material outside the system and causing less alteration of themolten material, for instance less oxidation and contamination of themolten metal. This is a first advantage over the systems known in theprior art in which molten material often drips from the mobilecontainer, which results in needless loss of material and safetyproblems. This is the case of the “Hodler system” which also presentsthe propensity to cause important alteration to the molten material, dueto the relatively long transportation time mainly outside the crucible.The system according to the invention significantly improves thissituation since the transportation of the molten material before pouringis simplified in a significant way.

A second advantage of the system according to the invention is thatpouring can easily be controlled and stopped by reversing or stoppingthe movement of the second container without loss or risk of alterationof the molten material since the molten material which is not pouredremains inside the second container and thus inside the first container.

A third advantage is that the system is very compact, since the secondcontainer does not leave the first container. It means, firstly, thatthe occupied area on the floor is smaller and, secondly, that the systemis much cleaner since the elements of said system are concentrated in arelatively smaller volume, thus requiring less protecting means toconstrain to a particular area the high temperatures, the heatradiation, the polluted atmosphere, the molten material ejection and thelike.

A fourth advantage is that the heat remains subtantially inside thesystem up until the metal is actually poured, because no molten metal istransported outside the first container until it is poured. In the“Hodler system” of the prior art, the mobile container is transportedaway from the crucible in such a way as to lead to a larger loss ofenergy and to subject a larger area to safety hazard.

A fifth advantage of the system according to the invention is that onlyrelatively small and simple movements are involved in the tapping andpouring operations since the second container remains inside the firstcontainer. No complex movement is required since the second containermoves with respect to the common inner wall and thus the movement is atleast to some extent guided, i.e. for instance only a certain type orcertain types of movement, such as a translation or a rotation of thesecond container with respect to the first container, are possible.Moreover, the system may be totally automatized without complexmechanisms thanks to its simplicity.

Thus a simpler more compact system is obtained, which means lessexpensive as well. Since the system is simpler and more compact andsince there is less heat loss and less risk of molten material dripping,contamination and safety hazard, the system is easier to install andmaintain. Furthermore, since the implied movement is quite small and canbe executed in a simple way, the movement can be controlled moreaccurately, thus leading to a more accurate amount of poured moltenmaterial.

Thus the characteritics of the invention provide an at least partialsolution to the mentioned problems of the prior art tapping and pouringsystems, said problems being very specific to high-temperature moltenmaterials. Indeed, the circumstances in which these systems are used arevery particular, due to the extreme temperatures, the intense radiation,the polluted surrounding atmosphere, the molten metal ejections and soforth. Many normal material and devices cannot be used in thesecircumstances and any new improvement must be designed keeping in mindthe specific context involved.

In particular, it should be noted that the system according to theinvention is simpler, more compact, cleaner, less expensive and easierto install and maintain but yet provides for greater accuracy in pouringamounts of molten material, surprising though it may seem.

SHORT DESCRIPTION OF THE DRAWINGS

These and further aspects of the invention will be explained in greaterdetail by way of example and with reference to the accompanying drawingsin which

FIG. 1 a shows a schematic cross-section representation of an example ofthe system according to the invention, in operation, while the secondcontainer is entirely plunged into the first container bath;

FIG. 1 b shows the system of FIG. 1 a while the second container liquidlevel is slightly above the overflow limit, but while the moltenmaterial does not overflow yet;

FIG. 1 c shows the system of FIG. 1 a while the second container liquidlevel is above the overflow limit and while the exceeding moltenmaterial is flowing over the brim of an aperture;

FIG. 1 d shows a top view of the system of FIG. 1 c;

FIG. 2 a shows a schematic cross-section representation of an example ofthe system according to the invention, while not in operation, i.e.without any molten material in the containers;

FIG. 2 b shows the second container of the system of FIG. 2 a, whilesaid second container is completely separated from the first container;

FIG. 3 a shows a schematic cross-section representation of anotherexample of the system according to the invention, in operation, whilethe second container liquid level is above the overflow limit and whilethe exceeding molten material is flowing over the brim of an aperture;

FIG. 3 b shows a top view of the system of FIG. 3 a; and

FIG. 4 shows a schematic cross-section representation of yet anotherexample of the system according to the invention, in operation, whilethe second container is at the pouring position.

The figures are not drawn to scale. In general, like references numeralsrefer to like parts.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

According to a first aspect, the invention concerns a system (2) fortapping and pouring high-temperature molten material, for instance fortapping molten metal from a crucible (4) and pouring it into a mould.

FIG. 1 a shows a schematic cross-section representation of an example ofthe system (2) according to the invention, in operation, while thesecond container (6) is entirely plunged into the first container bath(8). In operation, the first container (4) or crucible contains indeed abath (8) of molten material, for instance a molten metal, whichcommunicates through a first channel (20) for instance with anothercrucible, although it will be clear for the person skilled in the artthat such a communication channel (20) is neither essential norcompulsory to the invention.

A second channel (18) or hollow inner tube is located substantiallyinside the first container (4) and extends from above the level La ofthe first container bath (8) to below the bottom of the first container(4), thus forming a inner wall (26), common to both the first container(4) and the second container (6). In said common inner wall (26)delimiting the second channel (18) from the first container (4) and thebath (8) contained therein, there is an aperture (12) or exit of whichthe lower level L_(A) has to be above the level L_(B) in order toprevent the molten material of the bath (8) from flowing through theaperture (12) into the second channel (18). Said second channel (18) mayhave a cylindrical shape and may be surrounded by the liquid bath (8).

A second container (6) is arranged inside, i.e. fit in, the firstcontainer (4) in such a way as, first, to be substantially in contactthrough a joint (22) or not with the wall (26), secondly, to extendaround the second channel (18), for instance to form a cylindrical shapearound said channel (18) if said channel (18) has a cylindrical shape,and, thirdly, to be capable of moving vertically only. In order toproduce the vertical movement of the second container (6), i.e. in orderto lift it and to lift it down, some means for lifting the secondcontainer (6) are provided. In FIG. 1 a , a jack (16) is represented andcontrols the second container's (6) movement via some rods (14).Nonetheless, it will be clear for the person skilled in the art thatsome other means may be used without departing from the invention.

The term “inside” in “the second container (6) remains inside the firstcontainer (4)” must be understood broadly, i.e. it means that the secondcontainer (6) stays in operation in or slightly above the firstcontainer (4) in such a way as, on the one hand, the movement of thesecond container (6) when in operation can be operated by a relativelysimple mechanism and, on the other hand, the second container (6) staysin the vicinity of the first container (4), thus causing a relativelysmall heat loss.

FIG. 1 b shows the system (2) of FIG. 1 a while the second containerliquid level is slightly above the overflow limit, i.e. the level L_(A).In other words, FIG. 1 b is a schematic representation of the system (2)of FIG. 1 a at an instant just before some liquid of the secondcontainer liquid bath (10) goes through the aperture (12). Or, in stillanother words, while FIG. 1 a shows the second container (6) at thefilling position, FIG. 1 b shows said second container (6) at thepouring position, just before the pouring step actually occurs.

FIG. 1 c shows the system (2) of FIG. 1 a while the second containerliquid level is above the level L_(A) and while the exceeding moltenmaterial (24) is flowing over the brim of the aperture (12). It will beclear from the person skilled in the art that there may be no aperture(10) and that the exceeding molten material (24) may flow through anoverflow outlet system, over the brim of the top of the second channel(18) or via any means of letting the liquid flow without departing fromthe invention.

FIG. 1 d shows a top view of the system (2) of FIG. 1 c. Both containers(4, 6) are shown and the exceeding molten material (24) is also shownwhen falling with gravity through the second channel (18). The dashedline A represents the plan according to which the cross-section of FIG.1 c is made. The means (16) for lifting the second container (6) is notshown in FIG. 1 d in order to keep said figure as clear as possible.

So, the successive steps shown in the FIG. 1 a , 1 b and 1 c illustratean example of a way of operating the system (2) according to theinvention in order to tap a particular amount or volume of moltenmaterial from the bath (8), lift it in a second container (6) and pourit through an aperture (12) in a channel leading for instance to amould. By lifting the second container (6) until it reaches particularlevel, the volume it is capable to hold is reduced and depends on saidparticular level. Subsequently, the overflowing molten material (24)that will may be poured into the mould depends on the level to which thesecond container (6) is lifted. This is an important advantage, forinstance in die-casting operation but also on other applications, since,on the one hand, the accuracy of the volume of molten material deliveredto a mould is an important requirement in order to waste as less metalas possible, and, on the other hand, the system (2) may be used fortapping and pouring different volumes or quantities without having toalter the components of said system (2). In other words, in operation,the molten material that is poured into e.g. a mould may consequently becontrolled by the level to which the second container (6) is lifted.

In order to lift the second container (6) at a particular level anddeliver an accurate volume, means for stopping the means (16) forlifting the second container (6) may be provided. For instance a jack(16) with a carriage stop (32) may be used. Said means for stopping thelifting movement, for instance an adjustable carriage stop (32), may besuch that it is possible to adapt said means in order to change thevolume of liquid to be poured. In order words, by controlling themovement of the jack (16) for instance, it is possible to control thevolume to be poured. As explained above, this is an important advantageover the tapping and pouring systems as known in the art.

One notable advantage of the embodiment of the system (2) shown in FIG.1 a , 1 b and 1 c is that, during the operation, the molten materialstays, at least for some time heated by the molten material surroundingthe inner tube (18), thus creating less heat and less contamination.

FIG. 2 a shows a schematic cross-section representation of an example ofthe system (2) according to the invention, while not in operation, i.e.without any liquid in the containers (4, 6). In particular, a firstmaximum volume VI is shown, this is the volume that can be contained bythe second container (6) while fit into the first container (4). Thevolume VI is delimited by the wall (26), the walls of the firstcontainer (6) and the dashed line that would be the level of liquid inthe second container (6) if it was full to the brim, for instance at thefilling position.

In contrast, FIG. 2 b shows the second container (6) of the system (2)of FIG. 2 a, while said second container (6) is completely separatedfrom the first container (4), but, nonetheless, in the same orientationand configuration as the orientation and configuration shown in FIG. 2a. By the expression “in the same configuration”, it should beunderstood that for instance no valve has been opened between the secondcontainer of the system shown in FIG. 2 a and the second container ofthe system shown in FIG. 2 b. In particular, the second maximum volumeV₂ is represented and is the volume that can be contained by the secondcontainer (6) while completely separated from the first container (4).The second maximum volume V₂ is different from the first maximum volumeV₁. In particular, in the case illustrated in FIG. 2 a and 2 b, thevolume V₂ is smaller than volume V₁ and the volume V₁ is larger than 0.The difference of volume highlighted here is a characteristic of a classof systems (2) according to the invention, the class of systems (2) inwhich, in operation, the second container (6) only translates withrespect to the common inner wall (26). In operation, during the processof lifting the second container (6) out of the bath (8), from a certainmoment on, the volume that can be contained by the second container (6)is not anymore equal to V₁ and decreases towards V₂.

In addition to the volumes V₁ and V₂, the volumes V₃ and V₄ may bedefined. The third volume V₃ is defined as the maximum volume of moltenmaterial which can be contained into the second container (6) while themeans (16) for moving said container bumps into the adjustable carriagestop (32) when said carriage stop (32) is at its highest position.

The fourth volume V₄ is shown on FIG. 1 c and 4 and is defined as themaximum volume of molten material which can be contained into the secondcontainer (6) while the means (16) for moving said container bumps intothe adjustable carriage stop (32), said carriage stop (32) being in aparticular intermediate position.

Subsequently, the difference between the first maximum volume V₁ and thethird volume V₃ and the difference between said first maximum volume V₁and the fourth volume V₄ represent, for a particular system according tothe invention, the maximum volume of exceeding molten material that mayexit the containers, respectively while the carriage stop (32) is at itshighest position and while the carriage stop (32) is at a particularintermediate position. However, in order to calculate the accurateexceeding volumes that may exit the containers as explained, one mustsubtract from these differences of volume the possible small quantity ofmolten material which may leak through the joint (22), said quantitybeing controlled and independent of the level of molten material L_(b)of the first container (4). This shows the role of the adjustablecarriage stop (32) and illustrates one of the advantages of the system(2) according to the invention, i.e. that an accurate volume of moltenmaterial may be poured even if the level of liquid of the firstcontainer (4) varies slightly up or down with respect to its initiallevel.

It should be noted that the second container (6) shown in FIG. 2 b isdisassembled from the system (2) according to the invention. Indeed, asexplained above, in operation, the system (2) according to the inventionis such that the second container (6) is arranged inside the firstcontainer (4) and remains in it throughout the entire operation oftapping and pouring.

In one embodiment of the system (2) according to the invention, thesecond maximum volume Vp is substantially equal to zero.

In yet another embodiment of the system (2) according to the invention,in operation, the exceeding molten material (24) flows through an exitin a third channel (28), which starts in an inner wall common to thefirst container (4) and to the second container (6), said exit beingformed by a brim, an edge or a part of an edge of said wall, the means(16) for moving being then for moving the second container (6) up anddown said wall. A schematic cross-section representation of said system(2), in operation, is shown in FIG. 3 a. The second container liquidlevel is above the overflow limit and the exceeding molten material (24)is flowing through the third channel (28). The second container (6) isfit into the first container (4) in such a way as to be substantially incontact via the joint (22) with said first container (4), to be capableof moving vertically in respect to the first container (4) and to bealso capable of holding a bath of liquid (10). In this particularembodiment of the system (2) according to the invention, the secondcontainer (6) has a shape which may be generated by the rotation of a“L” around an vertical axis, even though it will be clear for the personskilled in the art that the second container's (6) shape may bedifferent without departing from the invention.

FIG. 3 b shows a top view of the system of FIG. 3 a. The dashed line Brepresents the plan according to which the cross-section of FIG. 3 a ismade. The means (16) for lifting the second container (6) is not shownin FIG. 1 d in order to keep said figure as clear as possible.

One notable advantage of the embodiment of the system (2) shown in FIG.3 a is that the construction is simple, i.e. there is no need ofinstalling an inner tube (18) in the first container (4).

It will be clear for the person skilled in the art that the volumes V₁,V₂, V₃ and V₄ and their meaning also apply to the embodiment of thesystem according to the invention as illustrated in FIG. 3 a and 3 b.

In another embodiment of the system according to the invention, inoperation, in the second container (6) executes a rotation with respectto a rotation axis linking both containers. The rotation axis is thecommon inner wall mentionned above. The characteristic stating that thecommon inner wall (26) comprises an exit must be understood by thefollowing meaning: said exit may be formed in the common inner wall (26)or located in the vicinity of said common inner wall (26) with departingfrom the system (2) according to the invention.

FIG. 4 shows another embodiment of the system (2) according to theinvention while the exit (12) is an aperture in the inner wall (26).This embodiment is very similar to the system (2) shown in FIG. 1 a , 1b, 1 c and 1 d.

In yet another embodiment of the system (2) according to the invention,in operation, the high-temperature molten material is a molten metal,such as aluminium, tin, lead or any other metal or alloy of metals. Itmay also be a molten glass.

By high-temperature molten material, it must be understood that theconcerned material has a melting point above 0 Celsius degrees.

In yet another embodiment of the system (2) according to the invention,the material is a metal or an alloy of metals having a melting pointcomprised between 0 Celsius degrees and 1000 Celsius degrees. The alloyis, in a particular embodiment, an alloy of metals having a low meltingpoint.

In yet another embodiment of the system (2) according to the invention,the molten material is a molten metal and the joint (22) is generallyentirely plunged in the bath (8) at any time of the operation of tappingand pouring molten material. Moreover, according to a preferredembodiment, in operation, the system (2) is such that the level L_(A) isonly slightly higher than the level L_(B). This slight differencebetween the level L_(A) and the level L_(B) guarantees that thedifference between the pressure at the vicinity of the joint (22) in thesecond container (6) and the pressure at the vicinity of the joint (22)in the first container (4) stays relatively small, thus reducing thepressure on said joint (22) and the quantity of molten material leakingthrough said joint (22).

It will be clear for the person skilled in the art that the system (2)according to the invention may be used for getting samples of moltenmaterial without departing from the invention.

In short, the invention can be described as follows: System (2) fortapping a high-temperature molten material, especially a molten metal,from a bath (8) and pouring it into a mould, comprising a mobilecontainer (6) capable of moving with respect to an element (26) in sucha way as, on the one hand, said container (6) may be plunged into thebath (8) to take some liquid and, on the other hand, lift the container(6) above a particular level for forcing the liquid to fall down withgravity through an aperture (10) along the wall. The system (2) does notimply high costs and allows to pour accurate volumes of molten material.

1. System (2) for tapping and pouring molten material having a meltingpoint above 0 Celsius degrees, comprising a first container (4) and asecond container (6) capable of being introduced into the firstcontainer (4); characterized in that the second container (6) isarranged inside the first container (4) and, in operation, remainsinside and in contact with the first container (4); the first (4) andsecond container (6) share a common inner wall (26) comprising an exit(12) for letting the molten material flowing out of the system (2); andthe system comprises means (16) for moving the second container (6) inrespect to the common inner wall (26) to and fro a filling position forfilling the second container (6) with molten material present in thefirst container (4) and a pouring position for pouring molten materialfrom the second container (6) through the exit (12).
 2. System (2)according to claim 1, characterized in that the common inner wall (26)is formed by a vertically oriented hollow inner tube (18) arrangedinside the first container (4), the inner tube (18) having near a freeend the exit (12), in that the second container (6) is arranged aroundthe inner tube (18), and in that the means (16) for moving are formoving the second container (6) along the inner tube (18).
 3. System (2)according to claim 2, characterized in that the common inner wall isformed by an inner wall of the first container (4) and the exit isformed by a brim, edge or a part of an edge of said wall, and the means(16) for moving are for moving the second container (6) up and down saidwall.
 4. System (2) according to any one of the preceding claims,characterized in that, the first container (4) and the second container(6) are in contact at a point which remains in operation plunged intothe bath (8).
 5. System (2) according to any one of the precedingclaims, characterized in that, the first container (4) and the secondcontainer (6) are in contact at a point near which there is a joint(22).
 6. System (2) according to any one of the preceding claims,characterized in that it further comprises an adjustable carriage stopfor stopping the means (16) for moving the second container (6) at aparticular level.
 7. System (2) according to any one of the precedingclaims, characterized in that the molten material is a metal or a alloyof metals.
 8. System (2) according to claim 7, characterized in that thematerial has a melting point comprised between 0 Celsius degrees and1000 Celsius degrees.